The Advanced Art of Stop-Motion Animation: Digital Cinematography: Part 1
Controlling the aperture affects the amount of light coming into the camera through an iris-shaped mechanism inside the lens. Capturing light through exposures in photography is measured by f-stops (Figure 4.6), which are either half or double the amount of light in the previous stop. To increase aperture by one f-stop, for instance, means doubling the amount of light hitting the sensor.
The shutter speed consists of how long the shutter is open and exposes the sensor to light. Therefore:
• Wide aperture (lower f-stop number) = more light = faster shutter speed.
• Small aperture (higher f-stop number) = less light = slower shutter speed.
Placing a digital light meter directly in front of your central focus (like your stop-motion puppet) and pressing its meter button will help you determine which f-stop and shutter speed to use for getting the right exposure for the lighting situation you are using. This is pretty straightforward if you just have one puppet in a long or medium shot on stage for a simple scene. For a composition that requires a bit more depth to the puppet’s surroundings, there are a few other things to consider. Whatever is closest to your light source may have a lower stop than anything that is farther away in the background, so you may want to take a reading for both your foreground and background, and stop your camera at a point in between.
Depth of Field
These camera settings will also be affected by the depth of field you want for your shot. Depth of field refers to how much of the distance of your composition is in focus. For stop-motion, as opposed to live action, everything is scaled down to miniature size, including the distance between your camera and your subjects. In most cases you don’t want the audience to feel like they are watching a miniature set, but rather a world they will recognize as having a natural sense of distance. This natural feeling of distance will be accomplished mostly by having a wider depth of field where more elements are in focus. A shallow depth of field will mean that if you focus on the central part of your composition, the background and surrounding elements will be blurry. Shallow depth of field is typically caused by a lower f-stop and faster shutter speed, and a wider depth of field by a higher f-stop and slower shutter speed. For a happy medium in a basic animation scene, most stop-motion filmmakers set their camera in the area of f11 with a shutter speed of 1/2 to 1 second. Stopping at f16 or f22 will create a more extreme depth of field, and stopping at f8 or lower will soften the background. It all depends on the mood you are going for when telling your story.
The illustrated examples shown here show how different moods and effects are created through camera settings, and also through composition of the shot itself. For a happy, light, or comedic scene (Figures 4.7 and 4.8), the composition is usually flat, with the camera centered and perpendicular to the set. Figure 4.7 is shot with a shallower depth of field, which blurs the character in the background. Figure 4.8 is shot with a wider depth of field, so the whole scene is in focus and the faces of both characters are much clearer. This clarity is important for a playful scene like this and communicates the relationship between the two characters.